Lindsay Graham on Syria, Libya and Afghanistan

"We overestimate our ability to determine outcomes" of other countries' internal problems, former Defense Secretary Robert Gates, adding, with regard to Syria, "I think that caution, particularly in terms of arming these groups and in terms of U.S. military involvement, is in order."

Former Defense Secretary Robert Gates said he would not have approved a rushed proposal to send military assets to Benghazi to halt the September 2012 attack on a U.S. diplomatic facility there, saying, "The one thing that our forces are noted for is planning and preparation before we send people in harm's way, and there just wasn't time to do that."

Miss the second half of the show? Watch the second half of our interview with former Secretary of Defense Robert Gates, plus author and poet Maya Angelou discuss her new book Mom & Me & Mom.

"Anybody who knows me knows that my mother was the dominating and shaping force of my life," said "Face the Nation" host Bob Schieffer on Mother's Day, reciting a poem he wrote in 2006 about his mom's special place in his heart.

Acclaimed poet and author Maya Angelou spoke with "Face the Nation" about what motherhood means to her on Mother's Day, recalling stories from her own childhood and discussing her new book, "Mom & Me & Mom."

Former Secretary of Defense Robert Gates rebuts critics of the administration's response to the tragedy in Benghazi, saying he would have made the same decisions if he was head of the Pentagon at the time. He also addressed the war in Afghanistan, along with the crises in Iran and North Korea.